School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, China.
Department of Neurosurgery, The First People's Hospital of Wenling, Wenling, 317500, China.
Free Radic Biol Med. 2023 Jun;202:76-96. doi: 10.1016/j.freeradbiomed.2023.03.021. Epub 2023 Mar 29.
Glioma is the most common primary malignant brain tumor with poor survival and limited therapeutic options. Chelerythrine (CHE), a natural benzophenanthridine alkaloid, has been reported to exhibit the anti-tumor effects in a variety of cancer cells. However, the molecular target and the signaling process of CHE in glioma remain elusive. Here we investigated the underlying mechanisms of CHE in glioma cell lines and glioma xenograft mice model. Our results found that CHE-induced cell death is associated with RIP1/RIP3-dependent necroptosis rather than apoptotic cell death in glioma cells at the early time. Mechanism investigation revealed the cross-talking between necroptosis and mitochondria dysfunction that CHE triggered generation of mitochondrial ROS, mitochondrial depolarization, reduction of ATP level and mitochondrial fragmentation, which was the important trigger for RIP1-dependent necroptosis activation. Meanwhile, PINK1 and parkin-dependent mitophagy promoted clearance of impaired mitochondria in CHE-incubated glioma cells, and inhibition of mitophagy with CQ selectively enhanced CHE-induced necroptosis. Furthermore, early cytosolic calcium from the influx of extracellular Ca induced by CHE acted as important "priming signals" for impairment of mitochondrial dysfunction and necroptosis. Suppression of mitochondrial ROS contributed to interrupting positive feedback between mitochondrial damage and RIPK1/RIPK3 necrosome. Lastly, subcutaneous tumor growth in U87 xenograft was suppressed by CHE without significant body weight loss and multi-organ toxicities. In summary, the present study helped to elucidate necroptosis was induced by CHE via mtROS-mediated formation of the RIP1-RIP3-Drp1 complex that promoted Drp1 mitochondrial translocation to enhance necroptosis. Our findings indicated that CHE could potentially be further developed as a novel therapeutic strategy for treatment of glioma.
神经胶质瘤是最常见的原发性恶性脑肿瘤，患者生存率低，治疗选择有限。白屈菜红碱（CHE）是一种天然的苯并菲啶生物碱，已被报道在多种癌细胞中具有抗肿瘤作用。然而，CHE 在神经胶质瘤中的分子靶点和信号通路仍不清楚。在此，我们研究了 CHE 在神经胶质瘤细胞系和神经胶质瘤异种移植小鼠模型中的作用机制。结果发现， CHE 诱导的细胞死亡与早期神经胶质瘤细胞中依赖 RIP1/RIP3 的坏死性细胞死亡有关，而不是凋亡性细胞死亡。机制研究表明，坏死性细胞死亡与线粒体功能障碍之间存在串扰， CHE 触发了线粒体 ROS 的产生、线粒体去极化、ATP 水平降低和线粒体片段化，这是 RIP1 依赖性坏死性细胞死亡激活的重要触发因素。同时，PINK1 和 parkin 依赖性线粒体自噬促进 CHE 孵育的神经胶质瘤细胞中受损线粒体的清除，用 CQ 抑制线粒体自噬选择性增强了 CHE 诱导的坏死性细胞死亡。此外， CHE 引起的细胞外 Ca2+内流引起的早期细胞质钙作为线粒体功能障碍和 RIPK1/RIPK3 坏死小体形成的重要“启动信号”。抑制线粒体 ROS 有助于中断线粒体损伤和 RIPK1/RIPK3 坏死小体之间的正反馈。最后， CHE 抑制了 U87 异种移植的皮下肿瘤生长，而没有明显的体重减轻和多器官毒性。总之，本研究有助于阐明 CHE 通过 mtROS 介导的 RIP1-RIP3-Drp1 复合物形成诱导坏死性细胞死亡，促进 Drp1 线粒体易位从而增强坏死性细胞死亡。这些发现表明， CHE 可能作为一种治疗神经胶质瘤的新的治疗策略进一步开发。
